Nitrite
San Francisco City Water System
Nitrite, closely related to the fertilizer chemical nitrate, comes from urban runoff and from fertilizer applied to agricultural lands to pollute drinking water. Nitrite is significantly more toxic than nitrate. Excessive nitrite in water can cause oxygen deprivation in infants and increase the risk of cancer.
19
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | N/A | 0 | 0 | N/A |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | N/A | 0 | 0 | N/A |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | ND | 16 | 0 | ND |
| 2019 | ND | 3 | 0 | ND |
ppm = parts per million
State and national drinking water standards and health guidelines
EPA Maximum Contaminant
Level (MCL) 1 ppm
The legal limit for nitrite, established in 1991, was based on the rate of conversion of ingested nitrate into nitrite in adults. This limit may not fully protect against the risk of cancer due to nitrite exposure.
ppm = parts per million
All test results
| Date | Lab ID | Result |
|---|---|---|
| 2018-01-11 | 9553-007-1115 | ND |
| 2018-03-06 | 9553-004-1031 | ND |
| 2018-03-06 | 9553-008-0914 | ND |
| 2018-03-08 | 9553-006-0925 | ND |
| 2018-06-12 | 9590-004-1058 | ND |
| 2018-06-12 | 9590-008-0930 | ND |
| 2018-06-12 | 9590-006-1012 | ND |
| 2018-07-17 | 9553-007-0519 | ND |
| 2018-09-25 | 9553-006-0930 | ND |
| 2018-09-25 | 9553-004-0910 | ND |
| 2018-09-25 | 9553-008-0950 | ND |
| 2018-10-17 | 9553-007-0730 | ND |
| 2018-12-11 | 9553-006-0915 | ND |
| 2018-12-11 | 9553-007-0740 | ND |
| 2018-12-11 | 9553-004-0845 | ND |
| 2018-12-11 | 9553-008-1045 | ND |
| 2019-06-17 | 9553-006-1206 | ND |
| 2019-06-17 | 9553-007-0905 | ND |
| 2019-06-17 | 9553-008-1106 | ND |